Apparatus for the wet treatment of copy material



y 1966 w. LlMBERGER 3,252,478

APPARATUS FOR THE WET TREATMENT OF COPY MATERIAL Filed April 26, 1963 WALTER LIMBERGER Wrnvroe [IN IN 6 Claims. 61. 137-565) This invention relates to an apparatus for the wet treatment of copying material in a liquid bath forming part of a copying device comprising a treatment trough to be filled with treatment liquid and a supply container for treatment liquid associated therewith, the supply container communicating with the treatment trough via two ducts one of which includes a pump, this duct extending from the top into the treatment trough and terminating above its bottom while the other one serves as a return duct.

It is known to arrange in such devices a leakage-type pump, for example a gear pump, within the lower part of the housing, or below the supply container, the inlet nipple or port of the pump being connected to the lower part of the supply container while the discharge nipple or port is connected to a conduit which is inserted from the top into the treatment trough and terminates above its bottom. If the pump is stopped, the so-called syphon efifect is utilized for emptying thetreatment trough. It is also known to provide in such devices a return duct through which excess treatment liquid flows out and returns into the supply container.

The known return ducts must have a considerably larger cross-sectional area than the pump discharge duct because otherwise they cannot fulfill their purpose. These large cross-sectional areas are disadvantageous. Functionally the known return ducts are afflicted with the drawback that air is always entrained in the circuit of the treatment liquid, when the pump is kept running while the appartus is switched on, so that intense oxidation of the treatment liquid will take place also within the supply container. Thereby the eilectiveness and the service life of a liquid charge are considerably decreased.

In the described conventional system it is further disadvantageous that the treatment liquid fiows in an open circuit into which air not ony constantly enters through the return duct but is also aspirated in dependence on the flow rate of the liquid, whereby oxidation of the liquid occurs.

It is an object of this invention to avoid these drawbacks and, at the same time, to provide a device whose utility is not limited to a special construction of the treatment trough. It is also an object of this invention to provide means for enabling existing devices having no supply container to be equipped with one without great expenditure and without necessitating replacement of important parts.

In order to avoid the drawbacks of the known opencircuit pumping methods the invention provides that the treatment liquid, i.e. the liquid in the treatment trough as well as the liquid in the pump and ducts is circulated in a closed circuit in which, by means of a vacuum generated in the supply container by discharging the treatment liquid into the trough, the excess treatment liquid is sucked out of the trough. By this means not only the turbulence afilicting known pump circulation systems is avoided but, in addition, there is afforded a smooth return flow of the excess treatment liquid, which is substantially free of air, from the trough.

The apparatus according to the invention is characterized by the fact that the supply container is hermetically closed and serves as a secondary pump which, after the United States Patent filling of the treatment trough up to the predetermined liquid level, automatically becomes effective to aspirate the treatment liquid.

Thus the invention virtually provides a twin pump system in which a motor-driven pump serves to discharge the treatment liquid into the treatment trough and another pump becomes automatically eflfective in dependence on the degree of filling of the trough for sucking ofi treatment liquid. The supply container is made of rigid material in order to avoid deformation when the vacuum is generated.

According to the invention the return duct, which is connected to the supply container in an air-tight manner, extends advantageously from the top into the treatment trough and terminates at the predetermined liquid level in the treatment trough. By the introduction of the return duct from the top any necessity of especially profiling the side walls of the trough is avoided and the two ducts may be arranged on existing vessels without any difficulties.

Advantageously the mouth of the return duct is disposed in a plane parallel to the liquid level in the treatment trough and directed downwardly.

Another advantageous feature is seen in the fact that the return duct has the same cross-sectional area as the ump discharge duct. Preferably the return duct and the pump discharge duct are made as an integral piece. The ducts may, for example, be disposed in parallel relation side by side, yet in the zone of the mouth within the trough the return duct is made shorter than the pump discharge duct. According to a particular embodiment the pump discharge duct and the return duct are disposed concentrically with respect to each other, the return duct being the outermost.

According to another advantageous embodiment at least the ends at the trough of the duct or ducts are made of rigid material forming return bends or goosenecks whereby they may be hooked onto the treatment trough. For this purpose clips may be arranged on the return bend for mounting the ducts on the trough.

In the following the invention shall be described in detail in connection with the drawing showing several embodiments by way of example.

In the drawing:

FIG. 1 is a vertical sectional view of an apparatus ac-- cording to the invention;

FIG. 2 is a detail view of a special feature of the apparatus according to the invention; and

FIG. 3 is a detail view of a modification of the elements shown in FIG. 2.

In FIG. 1 the main parts of the developing apparatus are shown schematically. A base 1 of the apparatus supports a treatment trough 2 having guide elements 3, 4 and 5 arranged therein which serve to guide layer carrying sheets through the treatment bath to a pair of squeezing and transporting rollers 6 and 7 arranged above the treatment trough. The rollers and drive elements are journaled in mounting walls 8 in a manner known per se. The rollers 65, 7 are connected via a transmission 9 with a motor 10. The entire apparatus is closed by a cover, not shown, in conventional manner and may be provided in also conventional manner with exposure means not shown. The motor it) is connected with an energy source, symbolized by the mains 13, by leads 11 and 12. The lead 12 includes the main switch 14 for the apparatus which may be arranged on a table 15 of which only a part is shown.

Below the table 15 a housing 16 is disposed of which only the contours are shown diagrammatically. This housing 16 accommodates a supply container 17 for the treatment liquid. The supply container consists of rigid material, for example of plastic, and is supported by brackets 37 and 38. The supply container is provided with connecting nipples 18, 21 and, if desired, may have Patented May 24:, 1966- a tightly scalable filling nipple which normally is hermetically closed. The first connecting nipple 18 is arranged at the top of container 17 and has a return duct 20 connected thereto in an air-tight manner by means of a sealing stopper or a rubber seal 19. The other connecting nipple 21, arranged at the bottom, is sealingly connected with the inlet port 32 of a pump 22 whose discharge port 23 communicates via a flexible hose 24 with a discharge duct 25. The motor of the pump unit is connected via the electrical leads 26, 27 with the leads 11, 12 at a location behind the main switch 14 whereby the pump motor is energized simultaneously when the apparatus is switched on.

The return duct and the discharge duct extend upwardly through an aperture in a plate 4-1 of the table 15 and an aperture 42 in the base 1 of the apparatus disposed laterally adjacent the trough 2. The ducts comprise goosenecks 28 and 29 extending over the edge of one side Wall 43 of the trough and straight nipple portions 3% and 31 connected thereto and extending downwardly. The nipple 36 terminates at the predetermined liquid level, or preferably a trifle lower, while the nipple 31 extends to a location adjacent the bottom 44 of the trough 2. The mouth of the nipple 39 is disposed horizontally and facing downwardly. The mouth of the nipple 31 is similarly disposed. In this case, however, it is possible, as shown in FIG. 3, to provide serrations 36 at the lower end of the nipple so as to maintain the mouth open even though the nipple 31 may engage the bottom 44 of the trough 2. The ducts 2t 25 may be made of rigid material and fixed to the apparatus or the trough 2, for example by bonding with an adhesive strip 45.

When the apparatus is switched on and the pump 22 starts running treatment liquid is pumped out of the supply container 17 into the trough 2 via supply duct 25. As soon as the liquid level reaches the mouth of the nipple 30 this mouth is closed whereby no air can enter the supply container 17 anymore. Depending on the volume of the vessel the liquid level in the trough 2 may rise slightly, e.g. by 0.04, above the mouth of the discharge of nipple 30. By means of the treatment liquid by the pump a vacuum is formed in the upper part of the supply container 17 causing a smooth back-flow of the excess treatment liquid through the return duct 20 into the supply container 17 without, however, exposing the mouth of the nipple 30 because the generation of such vacuum in the supply container 17 is a prerequisite for the return flow, the constantly maintained pumping of liquid assuring that the treatment liquid does not flow back through the discharge duct 25. This reversal of flow take place only after the pump 22 is stopped by opening the main switch 14; since the pump is located below the level of the stored liquid in container 17, it is always submerged and does not require any priming upon the next closure of the switch.

FIG. 2 shows a substantially integral combination of the discharge duct 25 and the return duct 2! in which, for the sake of clarity, the partition between these ducts wall is shown as an outwardly visible seam. At a suitable point, e.g. in the region of the goosenecks of these ducts they are provided with clamp 32 including a bifurcated clip 33 by which the gooseneck portion may be mounted on the side wall 43 of the trough 2 in a correct position.

FIG. 3 shows a concentric arrangement in which the return duct 20 surrounds the discharge duct 25. The concentric arrangement may, for example, be assured by spider-like projections 34, 35. Furthermore it is to be understood that the ducts are separated in the zone of the supply container 17 in a manner not illustrated. However it is also possible to extend the discharge duct 25 through the treatment liquid and to the pump.

It is to be understood that at least the return duct 20, which may also be termed a second connecting duct, is a pipe made of sufiiciently rigid material to prevent collapsing under the action of a vacuum. The discharge duct 25, which may also be termed the first connecting duct, preferably a pipe that consists of a similar material.

The pump 22 is designed for internal reverse leakage at standstill, i.e. the parts within the pump which are moving when pumping, for example impeller wheels, are spaced relative to the wall portions of the pumping chamber at least in certain zones of the chamber in such a manner that a return flow of liquid is possible through the stopped pump whereby the pump duct sustains the syphon action, with air escaping from duct 20. The pump may also be integral with a drive motor therefor.

What is claimed:

1. In an apparatus for the treatment of copying material in a liquid bath, in combination:

an upwardly open vessel for said treatment;

a closed container below said vessel holding a supply of liquid for said bath;

a first pipe forming a sealed connection with a lower part of said container and extending in a first gooseneck from above into said vessel, said first gooseneck terminating at a location close to the bottom of said vessel;

a second pipe forming a sealed connection with an upper part of said container and extending in a second gooseneck from above into said vessel, said second gooseneck terminating at a location elevated above the bottom of said vessel;

and pump means in said first pipe disposed below the liquid level in said container and operable to drive liquid from said container into said vessel by way of said first pipe with creation of suction in said second pipe whereby an overflow is aspirated and returned to said container through said second pipe upon the liquid in said vessel reaching the level of said elevated location, said pump means being constructed for internal reverse leakage on standstill.

2. The combination defined in claim 1 wherein said pipes are of substantially identical cross-sectional area.

3. The combination defined in claim 1 wherein said pipes are integrally interconnected.

4. The combination defined in claim 3 wherein said second gooseneck concentrically surrounds said first gooseneck.

5. In an apparatus for the treatment of copying material in a liquid bath, in combination:

an upwardly open vessel for said treatment bath;

a closed container below said vessel holding a supply of liquid for said bath; first duct means forming a sealed connection with the bottom of said container and extending into said vessel, said first duct means extending over a wall of said vessel and terminating at a location close to the bottom of said vessel; second duct means forming a sealed connection with the top of said container and extending into said vessel, said second duct means terminating at a location elevated above the bottom of said vessel;

and pump means in said first duct means disposed below said container and operable to drive liquid from said container into said vessel by way of said first duct means with creation of suction in said second duct means whereby an overflow is aspirated and returned to said container through said second duct means upon the liquid in said vessel reaching the level of said elevated location, said pump means being constructed for internal reverse leakage on standstill whereby said first duct means forms a syphon through said pump means on standstill of said pump means for transfer of said. liquid from said vessel to said container, said syphon constituting the sole means for returning said liquid from said vessel to said container at standstill of said pump means,

5 6 6. In an apparatus for the treatment of copying matainer into said vessel by way of said first pipe with terial in aliquid bath, in combination: creation of suction in said second pipe whereby an an upwardly open vessel for said treatment bath; overflow is aspirated and returned to said container a closed container below said vessel holding a supply through second P 9 P the hquld 111 Said ofliquid f saidlbath; 5 vessel reaching the level of said elevated location, a first pipe forming a sealed connection with the bottom Sald Pump means belng constructed for Internal of said container and extending in a first gooseneck reversal leakage on standstill from above into said vessel, said first gooseneck ter- References ga by the Examiner I rigging at a location close to the bottom of said 10 UNITED STATES PATENTS a second i e formin a sealed connection with the to 1,922,117 8/1933 Turner 137 563 P p g p 2,287,396 6/1942 Roth 137-563 X of said container and extending in a second gooseneck from above into said vessel, said second goose K 5 neck terminating at a location elevated above the 15 3O75551 1/1963 i X bottom of said vessel;

and pump means in said first pipe disposed below said CARY NELSON, Primary Examiner d I container an operable to drive l1qu1d from said con W. R. CLINE, Assistant Examiner. 

1. IN AN APPARATUS FOR THE TREATMENT OF COPYING MATETIAL A LIQUID BATH, IN COMBINATION: AN UPWARDLY OPEN VESSEL FOR SAID TREATMENT; A CLOSED CONTAINER BELOW SAID VESSEL HOLDING A SUPPLY OF LIQUID FOR SAID BATH; A FIRST PIPE FORMING A SEALED CONNECTION WITH A LOWER PART OF SAID CONTAINER AND EXTENDING IN A FIRST GOOSENECK FROM ABOVE INTO SAID VESSEL, SAID FIRST GOOSENECK TERMINATING AT A LOCATION CLOSE TO THE BOTTOM OF SAID VESSEL; A SECOND PIPE FORMING A SEALED CONNECTION WITH AN UPPER PART OF SAID CONTAINER AND EXTENDING IN A SECOND GOOSENECK FROM ABOVE INTO SAID VESSEL, SAID SECOND 